<?php
	/**
	* Global Search Engine for Moodle
	*
	* @package search
	* @category core
	* @subpackage search_engine
	* @author Michael Champanis (mchampan) [cynnical@gmail.com], Valery Fremaux [valery.fremaux@club-internet.fr] > 1.8
	* @date 2008/03/31
	* @license http://www.gnu.org/copyleft/gpl.html GNU Public License
	*
	* Index asynchronous updator
	*
	* Major chages in this review is passing the xxxx_db_names return to
	* multiple arity to handle multiple document types modules
	*/
	
	/**
	* includes and requires
	*/
	require_once('../config.php');

/// makes inclusions of the Zend Engine more reliable							   
	$separator = (array_key_exists('WINDIR', $_SERVER)) ? ';' : ':' ;				   
	ini_set('include_path', $CFG->dirroot.'/search'.$separator.ini_get('include_path'));require_login();

	require_once("$CFG->dirroot/search/lib.php");
	require_once("$CFG->dirroot/search/indexlib.php");

/// checks global search activation

	require_login();
	
	if (empty($CFG->enableglobalsearch)) {
		error(get_string('globalsearchdisabled', 'search'));
	}
	
	if (!has_capability('moodle/site:doanything', get_context_instance(CONTEXT_SYSTEM))) {
		error(get_string('beadmin', 'search'), "$CFG->wwwroot/login/index.php");
	} 
	
	try {
		$index = new Zend_Search_Lucene(SEARCH_INDEX_PATH);
	} catch(LuceneException $e) {
		mtrace("Could not construct a valid index. Maybe the first indexation was never made, or files might be corrupted. Run complete indexation again.");
		return;
	}
	$dbcontrol = new IndexDBControl();
	$update_count = 0;
	$indexdate = @$CFG->search_indexer_update_date;
	$startupdatedate = time();

/// indexing changed resources
	
	mtrace("Starting index update (updates)...\n");
	
	if ($mods = get_records_select('modules')) {
		$mods = array_merge($mods, search_get_additional_modules());
		
		foreach ($mods as $mod) {
			$class_file = $CFG->dirroot.'/search/documents/'.$mod->name.'_document.php';
			$get_document_function = $mod->name.'_single_document';
			$delete_function = $mod->name.'_delete';
			$db_names_function = $mod->name.'_db_names';
			$updates = array();
			
			if (file_exists($class_file)) {
				require_once($class_file);
				
				//if both required functions exist
				if (function_exists($delete_function) and function_exists($db_names_function) and function_exists($get_document_function)) {
					mtrace("Checking $mod->name module for updates.");
					$valuesArray = $db_names_function();
					if ($valuesArray){
						foreach($valuesArray as $values){
						
							$where = (!empty($values[5])) ? 'AND ('.$values[5].')' : '';
							$itemtypes = ($values[4] != '*' && $values[4] != 'any') ? " AND itemtype = '{$values[4]}' " : '' ;
	
							//TODO: check 'in' syntax with other RDBMS' (add and update.php as well)
							$table = SEARCH_DATABASE_TABLE;
							$query = "
								SELECT 
									docid,
									itemtype
								FROM 
									{$CFG->prefix}{$table}
								WHERE
									doctype = '{$values[1]}'
									$itemtypes
							";
							$docIds = get_records_sql_menu($query, array($mod->name));
							$docIdList = ($docIds) ? implode("','", array_keys($docIds)) : '' ;
							
							$query = "
								SELECT 
									id, 
									{$values[0]} as docid
								FROM 
									{$CFG->prefix}{$values[1]} 
								WHERE 
									{$values[3]} > {$indexdate} AND 
									id IN ('{$docIdList}')
									$where
							";
							$records = get_records_sql($query);
							if (is_array($records)) {
								foreach($records as $record) {
									$updates[] = $delete_function($record->docid, $docIds[$record->docid]);
								} 
							} 
						}
						
						foreach ($updates as $update) {
							++$update_count;
							
							//delete old document
							$doc = $index->find("+docid:{$update->id} +doctype:{$mod->name} +itemtype:{$update->itemtype}");
							
							//get the record, should only be one
							foreach ($doc as $thisdoc) {
								mtrace("  Delete: $thisdoc->title (database id = $thisdoc->dbid, index id = $thisdoc->id, moodle instance id = $thisdoc->docid)");
								$dbcontrol->delDocument($thisdoc);
								$index->delete($thisdoc->id);
							} 
							
							//add new modified document back into index
							if (!$add = $get_document_function($update->id, $update->itemtype)){
								// ignore on errors
								continue;
							}
							
							//object to insert into db
							$dbid = $dbcontrol->addDocument($add);
							
							//synchronise db with index
							$add->addField(Zend_Search_Lucene_Field::Keyword('dbid', $dbid));
							mtrace("  Add: $add->title (database id = $add->dbid, moodle instance id = $add->docid)");
							$index->addDocument($add);
						} 
					}
					else{
						mtrace("No types to update.\n");
					}
					mtrace("Finished $mod->name.\n");
				} 
			} 
		} 
	} 
	
	//commit changes
	$index->commit();
	
	//update index date
	set_config("search_indexer_update_date", $startupdatedate);
	
	mtrace("Finished $update_count updates");

?>